A tale of three systems : case studies on the application of architectural tactics for cyber-foraging

Cyber-foraging is a technique to enable mobile devices to extend their computing power and storage by offloading computation or data to more powerful servers located in the cloud or in single-hop proximity. In previous work, we developed a set of reusable architectural tactics for cyber-foraging systems. We define architectural tactics as design decisions that influence the achievement of a system quality. In this article we present the results of three case studies to validate the application of the tactics to promote their intended functional and non-functional requirements. The first two case studies focus on the identification of architectural tactics in existing cyber-foraging systems. The third case study focuses on the development of a new cyber-foraging system using the architectural tactics. The results of the case studies are an initial demonstration of the validity of the tactics, and the potential for taking a tactics-driven approach to fulfill functional and non-functional requirements for cyber-foraging systems. (C) 2019 Elsevier B.V. All rights reserved

The case for cyber foraging

In this paper, we propose cyber foraging: a mechanism to augment the computational and storage capabilities of mobile devices. Cyber foraging uses opportunistically discovered servers in the environment to improve the performance of interactive applications and distributed file systems on mobile clients. We show how the performance of distributed file systems can be improved by staging data at these servers even though the servers are not trusted. We also show how the performance of interactive applications can be improved via remote execution. Finally, we present VERSUDS: a virtual interface to heteregeneous service discovery protocols that can be used to discover these servers

Mobile, collaborative augmented reality using cloudlets

The evolution in mobile applications to support advanced interactivity and demanding multimedia features is still ongoing. Novel application concepts (e.g. mobile Augmented Reality (AR)) are however hindered by the inherently limited resources available on mobile platforms (not withstanding the dramatic performance increases of mobile hardware). Offloading resource intensive application components to the cloud, also known as "cyber foraging", has proven to be a valuable solution in a variety of scenarios. However, also for collaborative scenarios, in which data together with its processing are shared between multiple users, this offloading concept is highly promising. In this paper, we investigate the challenges posed by offloading collaborative mobile applications. We present a middleware platform capable of autonomously deploying software components to minimize average CPU load, while guaranteeing smooth collaboration. As a use case, we present and evaluate a collaborative AR application, offering interaction between users, the physical environment as well as with the virtual objects superimposed on this physical environment

A Catalog of Architectural Tactics for Cyber-Foraging

Mobile devices have become for many the preferred way of interacting with the Internet, social media and the enterprise. However, mobile devices still do not have the computing power or battery life that will allow them to perform effectively over long periods of time or for executing applications that require extensive communication or computation, or low latency. Cyber-foraging is a technique enabling mobile devices to extend their computing power and storage by offloading computation or data to more powerful servers located in the cloud or in single-hop proximity. This paper presents a catalog of architectural tactics for cyber-foraging that was derived from the results of a systematic literature review on architectures for cyber-foraging systems. Elements of the architectures identified in the primary studies were codified in the form of Architectural Tactics for Cyber-Foraging. These tactics will help architects extend their design reasoning towards cyber-foraging as a way to support the mobile applications of the present and the future

Empirical Validation of Cyber-Foraging Architectural Tactics for Surrogate Provisioning

Background Cyber-foraging architectural tactics are used to build mobile applications that leverage proximate, intermediate cloud surrogates for computation offload and data staging. Compared to direct access to cloud resources, the use of intermediate surrogates improves system qualities such as response time, energy efficiency, and resilience. However, the state-of-the-art mostly focuses on introducing new architectural tactics rather than quantitatively comparing the existing tactics, which can help software architects and software engineers with new insights on each tactic. Aim Our work aims at empirically evaluating the architectural tactics for surrogate provisioning, specifically with respect to resilience and energy efficiency. Method We follow a systematic experimentation framework to collect relevant data on Static Surrogate Provisioning and Dynamic Surrogate Provisioning tactics. Our experimentation approach can be reused for validation of other cyber-foraging tactics. We perform statistical analysis to support our hypotheses, as compared to baseline measurements with no cyber-foraging tactics deployed. Results Our findings show that Static Surrogate Provisioning tactics provide higher resilience than Dynamic Surrogate Provisioning tactics for runtime environmental changes. Both surrogate provisioning tactics perform with no significant difference with respect to their energy efficiency. We observe that the overhead of the runtime optimization algorithm is similar for both tactic types. Conclusions The presented quantitative evidence on the impact of different tactics empowers software architects and software engineers with the ability to make more conscious design decisions. This contribution, as a starting point, emphasizes the use of quantifiable metrics to make better-informed trade-offs between desired quality attributes. Our next step is to focus on the impact of runtime programmable infrastructure on the quality of cyber-foraging systems

Leveraging cloudlets for immersive collaborative applications

To enable immersive applications on mobile devices, the authors propose a component-based cyber foraging framework that optimizes application-specific metrics by not only offloading but also configuring application components at runtime. It also enables collaborative scenarios by sharing components between multiple devices